Are there any temperature parameters that should be met in a 3 ton, 14 seer w/heat pump used in cooling upstairs? We cannot get the unit to cool below 10 degrees of the outside temp. Example: if it's 95 outside, it will cool to 85 only. The unit is only 5 years old, but we've had this problem since day one. Should we be measuring the air temp coming from the vents w/thermomoter?